Ok, hopefully this is going to be an easy enough question to be answered.

When creating a horizontal nav, is there a best way to do so?

The way I learned would have been to float the nav to the left and use margins/paddings to space them out until they reached a certain point (usually the width of the site).

I found out on some sites I've seen that some nav's are created using relative positioning and that each word in the menu is set to a certain amount of pixels, is there much benefit in doing it this way?